Calvin and Hobbes looked at each other in amazement. They just couldn't believe that they found a real mertiger.

"I can't believe it!" said Hobbes. "Calvin, we found a mertiger! Many people hardly get the chance to see one."

"That's because we're not easy to find," explained the mertiger. "You need a good sense of searching and imagination to find us mertigers. But there are lots of other ways there aren't a lot of mertigers."

This amazed Calvin and Hobbes. "Like what?" they asked together.

The mertiger told the pair that while mertigers can easily keep predators like sharks from attacking them, there was something that threatened the lives of mertigers just like other sea creatures – marine pollution!

"There are all sorts of marine pollution," the mertiger said. "The worst is rubbish in the ocean."

"That explains why there were a lot of plastic bags in the ocean," Calvin said.

"Correct," the mertiger replied, "but there are ways you can prevent it from happening."

Calvin and Hobbes were actually interested in the mertiger's clever words. Maybe if they followed her advice, there could be more mertigers to see.

"Well, Miss Mertiger," replied Calvin, "it was great meeting you and we'll try to spread the word about preventing marine pollution. Wish we could stay longer, but Hobbes and I should be going. My family's about to leave."

"I understand," the mertiger told them. "It was great meeting you, Calvin and Hobbes."

"Bye, mertiger!" called Hobbes.

Calvin and Hobbes swam all the way to the surface.

Meanwhile, Calvin's parents were loading the car, getting ready to go. Just then, they saw Calvin carry Hobbes to the car.

"Calvin!" said Calvin's mother. "We haven't seen you all day. Where've you been?"

"We've been looking for a mertiger," replied Calvin. "And I've got some advice for you. When you go and buy groceries, try and use a reusable shopping bag. Also, don't use any plastic straws."

While Calvin's mother didn't believe him, she certainly decided to follow his advice. She wondered where he was told this stuff.

During the car ride back, Hobbes was still happy.

"I can't believe it!" he exclaimed. "I finally saw a mertiger."

"And just think," added Calvin. "If we tell everybody what the mertiger taught us about marine pollution, many people will be able to find more mertigers."

Just then, Hobbes whispered to Calvin, "By the way, you owe me a dollar."

THE END